The most honest, thorough and reasonable auto repair place I've found. They took two hours to diagnose the problems with my 2003 Mini Cooper - something that eluded Desert Mini of Las Vegas for two full days and part of a third (and they charged me a grand for the privilege - also see my review of the thieves at Desert Mini).
Another thing I like about Kensington is that they understand that people aren't made of cash. If they find problems with your car they help you prioritize, telling you which ones are urgent and which ones can reasonably wait. They also help you to save money by suggesting repairs to be done together to save labor costs. They show you what they have found, so you know what they're talking about (and you know they aren't just trying to get more money out of you).
I also had Kensington do repair work on my 1999 Jaguar XJ8. I had a coolant leak that I couldn't find (Jaguar put hoses seemingly by the dozen in these things) and I decided to have the timing chain tensioners replaced (getting rid of the old plastic ones for the new metal ones). Kensington did a very thorough job and for about $1K less than I was quoted by another independent shop. No one else touches my cars.